For the best guacamole you need ripe avocados — they give slightly when pressed. Do not skimp on the lime juice: it lifts the flavor and keeps the guacamole from turning brown. If you want it less spicy, leave the jalapeño out entirely or remove all the seeds and membranes. Coarse texture? Three to four pulses are enough. Creamy? Five seconds on setting 3 to 4. Guacamole keeps in the refrigerator for up to two days — covered with plastic wrap pressed directly onto the surface so no air reaches it.
An honest word on equipment: classic guacamole is traditionally made with a fork or a molcajete (mortar) — for a chunky, rustic texture that is still the best way. The Vitamix shines in two places: first, for the flavor paste (purée the onion, jalapeño, garlic, and cilantro smooth first, then fold in the avocado by hand — that way the flavors spread evenly without destroying the avocado). Second, for a fully smooth avocado purée when a creamy texture is what you want. If you want chunky guacamole and have only three minutes: a fork and a bowl will do.